Should I have a service minimum?
Short answer
Yes. Set it at the smallest job that's actually profitable for you to leave the shop. Below that, you lose money even when you 'win.'
Find the floor
Add up: travel time, setup, the smallest meaningful work, paperwork, and a margin. That's your minimum. If it's $250, say $250.
How to say it
'Our service minimum is $X, which covers the trip and up to an hour on site. Most jobs end up larger; this just makes sure it's worth showing up.' Honest, easy to defend, and self-selecting.
Ask your version of this question
This is one business owner-tested take. Your shop size, trade, and team change the answer. Ask the exact version inside Ask a Shop Owner and get a response grounded in how owners like you actually handled it.